Automatic telephone-switching apparatus



V v 1,633,684 June 1927' H. sENGEBUSCH AUTOMATIC TELEPHONE SWITCHING APPARATUS Filed Aug. 27, 1925 4 Sheets-Sheet l III-1+0! Hans 5am sbusch AUTOMATIC TELEPHONE SWITCHING APPARATUS Filed Aug. 27, 1925 4 Sheets-Sheet 2 Inusnlnr Hans Sen sbusch Juhe 28,1927. 1,633,684

H. SENGEBUSCH A AUTOMATIC TELEPHONE SWITCHING APPARATUS Filed Aug. 27 1925' 4 Sheets-Sheet 3 Hans Sangebusmh AUTOMATIC TELEPHONE SWITCHING APPARATUS Fild Aug. 27, 1925 4 Sheets-Sheet 4 [m7]? Hans Sengsbusch Patented June 28, 1927.

UNITED STATES PATENT OFFICE.

HANS SENGEIBUSCH,

OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO AUTOMATIC ELECTRIC INC, OF CHICAGO, ILLINOIS, A CORPORATION OF DELA- WARE.

AUTOMATIC TELEPHONE-SXVITCHING APPARATUS.

Application filed August 27, 1925. Serial No. 52,731.

My invention relates to step-by-step switching apparatus employed in automatic telephone exchanges, and is concerned, more particularly, with a new and improved switching mechanism of the type commonly It l) known as a selector, that is to say, a switch employed for automatically selecting and making connection with an idle trunk line leading to another selector or to a connector, as the case may be.

Such apparatus as'intimated above are disclosed in the patents to Keith, Erickson and Erickson, Nos. 815,176 and 815,321, both granted March 13, 1906. Although the switches described in these patents have no immediate bearing upon the present invention, the presentationof the case will be greatly facilitated if the known is vividly recalled, before an attempt is made to apprehend the new. I shall therefore give a brief account of the salient features and operations of the well known rotary and vertical switch shown and described in detail in the above patents.

The essential mechanism consists of a longitiildinally and axially movable shaft provided with wipers adapted to engage the terminals of trunk lines which are arranged in terminal. banks in groups in horizontal semi-circular rows or levels.

The switch as a whole involves suitable electromagnetically-actuated mechanism for stepping the shaft vertically upwards, thereby positioning the wipers opposite a certain. row of terminals containing the desired trunk or line, whereupon the shaft is moved radially to select the trunk or line within that group. In case of a selector, the vertical movement is controlled by the calling subscriber operating the usual calling device and the rotary movement takes place automatically, whi'e in a connector both movements are under the calling subscribers control.

The release of the switch is accomplished upon the subscribers abandoning the call and replacing their receivers, whereupon the release magnet energizes causing the shaft to rotate back by force of a spiral spring and to drop then vertically into its normal position by force ofgravity.

Summarizing the features of the usual vertical and rotary switch, which should be kept/ in mind in examining the present invention, the shaft, or rather, to say, the wipers describe an angular motion, viz, vertically upwards, horizontally within a certain level and back again, during release, along the same paths, each movement being controlled by a distinct and separate magnet. The switch is thus provided with three operating magnets, the vertical, the rotary and the release magnet, each executing solely the respective operation of the mechanism.

The principal object of the present invention is to reduce the product-ion cost and the maintenance expenses of'the mechanism by simplifying its operations and, consequently, eliminating sources of trouble.

It will be seen presently that my invention represents a complete departure from the usual,that is to say, that I employ entirely different and novel principles for operating the mechanism. The most conspicuous features, however, which distinguish my im proved switch from the old and well known apparatus will now be outlined.

I have adopted the usual terminal banks in which the contacts of trunks or lines are arranged in groups in horizontal rows or levels. This, of course, necessitates a vertical and rotary movement of the shaft carrying the usual set of wipers. The novel fea tures will therefore be found in the manner of positioning the wipers upon a desired set of contacts associated with a trunk line.

Instead of moving the shaft vertically upwards under the control of a special ver-' tical magnet, to position them opposite a desired row of contacts, I utilize gravitational force directively controlled by an opcrating magnet which absorbs the current impulses produced by the subscribers caling device and moves a barrel provided with helically arranged steps or notches. The shaft carrying the wipers is provided at its upper end with a cam which is normally resting upon that barrel and advances ververtically downwards by force of gravity. The helically arranged teeth ot the revolving barrel will thereby pass the supporting cam of the shaft, but the cam cannot take hold in any of the passing teeth due to the speed of the barrel and the inertia. of the shaft. Upon the cessation of the movement of the barrel, the cam attached to the shaft will engage the tooth corresponding to the number of steps taken. The wipers are now positioned opposite the desired level of bank contacts.

The rotary movement commences then, automatically in case ot a selector and under directive control in case of a connector. The rotary impulses are delivered to the same magnet as before, and the barrel provided with helically arranged teeth, advances again, in the same direction. However, the cam secured to the upper part of the shaft, is now inserted in one of the teeth, and the shaft follows tlerefore, the rotary movement, advancing the wipers along the contacts of the selected level, to select an idle trunk or a subseribers line, as the case may be.

The release of the switch is accomplished by again delivering current impulses to the same magnet and thereby continuing the rotary movement of the barrel and also of the shaft. advancing the wipers along the remaining contacts of the level. A projecting arm, secured to the shalt, will strike a helical runway shortly after the last contact set in a row is passed. and lift the shaft out of attachment with the revolving barrel, i. e., the cam provided at the upper part of the shaft, which tool: hold in a tooth upon termination 01' the vertical movement, will. lisengage that tootl The rotary, r storing operation of th barrel continues while the shaft rests with the projecting arm on the helical runway. T his arm is provided with a pin extending vertically upwards and adapted to be engaged by a release lever, forcing the arm and with it the shaii't, to

travel diagonally up along the helical runway into its normal position.

A spiral spring, having one end ecured to the spring housing which is ll a e tachcd to the drum and the other end to a release lever which rests against a stop. stores up energy during the rotation oi the barrel, gradual y increasing the tension, of the release lever against the st op. Th stop will be removed momentarily shortly before the final step is taken by the barrel, i. c., snortly before the larrel completes a. full circle of 360 degrees. Accordingly, the release lever being set free, it will turn under the tension of the spiral spring, and, as has been intimated above, it will catch the pin secured to the projecting lever mounted on the shaft which at this instance is resting upon the helical runway, and carry the shaft up into its normal. resting position. The switch is now ready for subsequent use.

The above description which is necessarily incomplete on account of its brevity, will be amplified in the detailed explanation which is yet to follow, and the operations oi the mechanism will appear more clearly. However, it will be seen from the above that I have eliminated two operating magnets while the iunctions of the apparatus are fully preserved. In other words, I e1nploy in my improved switch only one single operating magnet as (Ollllhlffil with three separate magnets in the usual apparatus, and accomplish the same results without impairing the reliability of the operations. it will be apparent later on that there are a variety of other features and objects apart trom those suggested in the foregoing paragraphs.

I shall now present a detailed description of my invention and shall refer thereby to the attached dra *ings which 1 01.111 a part of this specification.

In Fig. 1, I have shown the interior of the switch mechanism seen from the terminal banks, with the bani-Is removed;

Fig. 2 is a side view 01' the switch illustrated in Fig. 1, showing also a cross section of the terminal banks;

Fig. 3 illustrates the same switch as seen from the top;

Fig. l is a cross section ol the barrel and ot the guide and release incchanisn'i shown in the upper part of Figs. 1 and 2;

5 illustrates the interlocking release mechan m in detail as seen trom line i l-"i l.

in lli r shows the working ot the guide mechanism as seen lrom line .ll-l oi Fig. i;

F" relation between the tl c leaf-9e mechanism after and before rcle eo fit:-

guide Fig.

9 is a detailed view illustrating); t manner oi: securing the release lever to t spring housing; and

f. ltlshows a schematic circuit for switch.

crating the Like pa" numbered alike in the drawings Fi s. l-l). inclusive, I shall, in the course at the following" disc ion, ret'er to a certain figure only it necessary for a clear innlerstamling. will be explained separately. 1 l ive not gone into a detailed illustration of the method of mounting the switch and the banks on. the supporting frame or rack, but merely indicated the manner or mounting in order to simplify the drawings and the description.

Referringnow to the drawings, it will be seen that the shaft 1 is provided, at its upper end, with a cam 2 having a projection 3. Secured tothe upper plate 4. of the U-shaped switch frame 5 is a bearing 6 as can best be seen in the cross-sectionFig. 4: A member 7 extends through bearing 6. The upper, barrel or drum-shaped, partof member 7 is provided with helically arranged teeth 8 in number corresponding to the levels of the terminal banks. The shaft rests suspended by projection 3 of cam 2 upon the incline 9 of the barrel 7, i. e., just in front of the first tooth. The lower end of member 7 extends through the bearing 6 and has secured to it the spring housing 10. The member 7 is thus adapted to be moved radially but not longitudinally. Inserted in the spring housing 10 is a spiral spring 11 and the release lever 12. loose connection is maintained between the spring housing 10 and the release lever 12 by spiral spring 11 which is secured to the spring housing at its outer end and to the release lever at its inner end. I i

The release lever 12 is provided with a circular groove 66. Two semi-circular washers 67 and 68 shown in Fig. 9, are inserted in said groove and secured to the spring housing 10 by means of a cap 69, as can readily be seen'from drawing Fig. eh This arrangement is provided for lreeping the release lever 12 in its proper place and permits an easy detachment. Aswill appear more clearly later on, when the barrel 7 rotates, the spring housing 10 participates in the movement. The release lever 12, however, cannot take part in the rotary movement of the drum because it rests against a stop 13 of an angular release member 1/1. The spiral spring 11 will, therefore, be wound up during the rotation of drum 7 and gradually increase the tension of the release lever 12 resting against stop 13. i

The shaft 1 extends through the barrel 7 and through the release lever 12 inserted in the spring housing. Rigidiy fastened to the shaft by means of screw 15 is the shaftguide lever 16 provided with a pin 17 which positioned in front of the release lever 12. The guide lever 16 is normallyresting against a stop 18. I

The sequence of events will be brought out clearly as the description progresses. However,it will be advisable now to consider the vertical movement of the shaft and the operation of the shaft guide-lever 16, before proceeding with the description of details.

It will be assumed for this purpose that current impulses are delivered to the mag net designated 29 for rotating the barrel member 7 in a direction indicated by arrows in Fig. 3. As is shown in Fig. 1, the shaftis normally resting with the projection 3 of cam 2 upon the incline on barrel 7- preceding the first tooth. Upon the barrel taking its first step, this support is'withdrawn from the shaft cam, moving the shaft vertically upwards due to the incline at the normal po sition, i. e., the shaft is started with a tendency to move upwards, whereupon it drops vertically down due to gravitational force. If no other steps were taken by the barrel 7, that is, if only a single impulse were delivered to magnet 29, the shaft would drop down and projection 3 of cam 2 would engage the first tooth of the barrel 7 which tooth corresponds to the first level of the terminal banks. However, if a plurality of current impulses is delivered to the magnet, the barrel 7 continues to rotate rapidly in a buzzer-like manner, and the shaft advances vertically downwards by force of gravity. The projection 3 of cam 2 cannot engage any of the passing teeth due to the high speed of the barrel and the relative inertia of the shaft. Upon the termination of the vertical impulses, the projection 3 of cam 2 will on gage the tooth corresponding to that level; The shaft is guided during its vertical movement, by the guide lever 16, and the description of its function will best be followed by consulting Figs. 2, &7, inclusive. The end of the shaft guide-lever 16 is provided with a semi-cireular groove 19. Opposite this groove, just below and in line with it there is a roller 20 fastened to an angular support 21, which is pivoted upon member 22, the latter also furnishing the stop 18. A. spring 23 keeps the roller 20 in alignment with shaft guide-lever 16. Upon the support being withdrawn, the shaft commences to move vertically downward. The shaft guide-lever 16 passes stop 18 but takes hold, upon the guide-roller 20 by means of the semi-circular groove 19. By this arrangement, the shaft is smoothly guided in its vertical motion, and proceeds vertically downwards. The shaft extends through the lower plate 24 of the frame and is provided, at its lower end, with a set of wipers designated 25, 26, and 27. The wipers are in this manner advanced vertically and positioned opposite a desired row of bank contacts. Pin 17 secured to the shaft guidelever 16 is, thereby vertically displaced relative to the locked release lever 12.

Continuing the description of the mechanical details of the apparatus, it will be seen that the barrel member 7 is provided with a circular row of teeth indicated at 28. A magnet 29 located in front of the U-shaped switch frame and permanently fastened to it, is adapted, when energized, to attr ct its armature 3O pivoted at 31. This armature is provided with a dog 32 extending towards the circular row of teeth associated with barrel 7, and held in normal position by means of spring with its front part en gaging a tooth. Stop 3% is provided for limiting the movement of the dog 32, and detent 35 for preventing the barrel from falling back during rotation. A cam is permanently fastened to drum 7 provided for operating; the off-normal. spring set 3. The oil normal springs will be operated, i. 0., contacts and 39 will be closed and contacts 4-0 opened with the first step taken by the barrel, the direction of the movement being indicated by the arrows. Upon the barrel completing a full circle of 360 degrees, the olif normal springs will be operated again and brought into the position shown in the drawing Fig. he armature 30 is also provided with a projecting arm t1 holding an insulated pin l2, which extends through an openin l3 towards a pair of normally closed cons. ts ll. As will be seen later on, these contacts are located in the circuit of magnet 29 and will produce current impulses for automatically operating the magnet to execute the huntin movement of the wipers after they have been advanced vertically and positioned opposite a certain level. During the vertical movement of the wipers, these contacts, although operated, will be ineffective. Underneath the circular row of teeth, and secured to the barrel '7 is a pin 45. The purpose of this pin is to momentarily move the release lever ll shortly before the termination of the storing movement of the barrel, and its operation can best be explained by referring to Figs. 1: and 5.

It will be seen that the pin 4-5 is normal y located in front of the restoring lever which is hep in a normal position by spring it with he stop 13 engaging the relea e .a'm l2 and preventing the latter from torl-owing' the rotary motion of the barrel as explained previously. The pin 44") advances with the barrel in a direction indicated by the arrow in Fig. 5. UPON. the barrel tal ing its last step, i. e., upon its return to normal, the pin approaches the lever arm lei from the other side, indicated in dots, and lifl'ts the lever momentarily, thereby removing stop 13 and allowing the release arm 12 to eltect the restoration of the shaft in a manner to be presently explained.

The semi-circular member G l, which is sloping, helically upwards and fastened to he lower plate Ql of the switch frame. one the fastening screws being visi le at 6 s for restoring the switch shatt into its normal llOblclOll, and shall be conveniently termed hclical-restoring-runw: shortly helical runway. I shall next t :cribed these restoring operations, referrparlicularly to Fig.

Details, however,

best be seen in Figs. 5, 6, and 7.

in order to explain the restoring operations of the switch. it will be assumed that the wipers have been positioned oppo ite a desired row of contac as described. This vertical setting is followed by the rotary movementt' the shaft which is eitfected in a Sllllllftl' manner as was the vertical motion, i. e., the magnet 29 will again operate and rotate the barrel 7. At this time, however, the projection 3 of cam 2 of the shaft will have engaged the tooth corresponding to t e selected row of contacts, and the shaft will, therefore, participate in the rotary movement and advance the wipers along the contacts of the level. in search tor an idle trunk. The guide lever 16 follows the rotary movement of the shaft, disengaging the guide roller 20 and moving towards the helical runway. In following these operations with the help of Fig. 2, the rotary motion of the guide lever 16 with its associated pin 1'? must be visualized as taking place towards the observer. When an idle trunk is encountered, in case of a selector, or the wanted line in case of aconnector, the rotarv moven'ient ceases and the switch remains in the attained position throughout the duration of the call. The guide lever 16 and the release lever 12 will. be in a position relative to each other, as shown in Fig. 7.

l fheu the subscribers replace the receivers at the termination of the call, the magnet ene izes again and rotates the barrel 7 as before. The wipers ad 'ance along; the remaining contacts in the level, at this time, however, without any el'lect, and the guide lever advances towards the helical restoring runway 64-.

it s ould be ol'iserved at this point. that he restoring operation presentsan advane which is not to be uzuler-estimated. In usual switch the wipers return to normal along the setting; )aths. course, results in an uneven wear of conaets, i. e., the first few contacts will wear out more quickly than the contacts at the end (Iii the levels causing a variety of troubles, which can, in some cases, only be remedied by replacing the partly worn banks by new o: es. This expensive procedure is obviated in my improved switch, as all contacts receive equal wear.

Continuing the description of the restorint OptlfltiOllS, the guide lever 16 advances towards the helical runway 64 and strikes runway shortly after the wipers have lCt'l the last tcrniiinal set off the level. e guide lever 16, bei loi'ce l against the la of the runs.

will lift the shaft, the projection 3 of the shaft cam 2 disiges from the tooth of the barrel. The er continues to rotate, while the shaft, 1th its guide levers l6 engaging the runis carried vertically upward, since a tion of the barrel member 7 engages the 3. Upon the barrel taking its last step, i. e., upon completing a circle of full 360 degrees, the pin located underneath the ratchet part of the barrel, approaches the interlocked restoring lever 1% as shown in Fig. 5 and previously explained, and moves This, of

the lever 14 and with it the stop 13 momentarily, whereupon the release lever 12 is set free under force of the spiral spring 11, advancing in the direction indicated by the arrow in Fig. 7. The release lever 12 will catch the pin 1"? associated with the shaft guide 16 which is at this instance upon the highest portion of the helical runway, and carry the shaft guide 16, and with it the shaft, into normal position, where the shaft guide 16 engages the stop 18 and the release lever 12 the stop 13, while the projection 3 of the shaft cam 2 is positioned'again upon the incline of the ba "rel preceding the first helical tooth. The switch is now ready for subsequent use.

As will be recalled, the connections between the wipers and the operating circuits are maintained in the usual switch, by means of a flexible, insulated three-conductor cord, which follows the movement of the wipers. This arrangement is in'ipractical in the present switch, in view of the fact that the wipers describe a full circle of 360 degrees. In order to maintain the required connec tions, I have devised auxiliary wipers which follow the movements of the switch wipers. It will be seen from the drawings Figs. 1 and Qthat I have provided a shaft 47 which is longitudinally movablein bearings 18 and 49. Oneof these hearings is located in the lower plate 24 of the switch frame while the other is associated with an angular holder 50 attached to the back of the frame. The auxiliary wiper 51 consists of a pair of conductively connected springs extending between the two springs of theprivate or test wiper 25, and is fastened to the shaft 47 by means of an adjustable clamp 52. Auxiliary wipers 53and 54: serve ina like manner for maintaining the connections with the line wipers 26 and 27, respectively, and are, of course, insulated from each other. These latter wipers are secured to the shaft 47 by means of a clamp 55, which is shown separately in Fig. 8. The clamp has a forked projection extending into a groove 56 pro vided upon the line-wiper holder 57 which is rigidly fastened to the shaft 1 by means of a screw 58. The private or test wiper 25 is also rigidly fastened to the shaft 1 .by holder 59 and screw 60. The auxiliary wipers will, as can readily be seen, move up and down in synchronism with the switch wipers, and no interference Wlll occur duringthe rotary movement of the latter. The conductors will be attached to the terminals (31, 6'2 and 63 of the auxiliary private and line wipers, respectively.

I shall now explain the manner of mounting the switching apparatus upon a supporting frame or rack, as indicated in Figs. 1 and 2. As will be seen from these figures, the switch rests on two circular bars and 71 extending through the lower plates of 'mature 21 closes a circuit for the slow acting the individual switch frame, and having turned down projections extending through the upper plate, where they may be fastened by means of nuts. The rack consists essentially of two angle irons 72 and 73, which are fastened to the uprights in the usual manner. Clamps, such as 74; and 75 are provided for rigidly attaching the circular bars 70 and 71 holding the switch, to the angle irons of the supporting rack. The line terminal banks 76, and the test terminal banks 77 are secured to the bars'TO and 71 as usual, by means of clamps.

It will be apparent that the switch can be easily removed from its terminal banks and mounted again by merely loosening two nuts securing the mechanism to the circular supporting bars associated with the rack. It will also be obvious from the foregoing, that my improved switch presents many advantages not found in other apparatus. The switch as a whole, as well as each of the parts within a switch, permits easy adjustment because of being readily accessible, and proper operation is insured due to the simplicity of the mechanism.

I shall now explain the circuit shown in Fig. 10. The sequence of operation will thereby appear more clearly, and points which were not plainly brought out during the discussion of the mechanical details, will obviously suggest themselves in the course of the following considerations.

Referring now to Fig. 10, the circuit shown is designed for a switch as described above, where the apparatus works as a selector switch, '1. e., a switch accessible to the subscribers individual line switch or to another selector, and adapted to select an idle trunk in a certain group of trunks, located in horizontal rows or levels, and leading to other selectors or to connectors.

When this switch is taken for use by a line switch or by a preceding selector, as the case may be, the line relay 20 operates over a circuit including its two windings, armatures 11 and let of the switching relay 10, and the trunk conductors 5 and 7. Ar-

rclease relay 30. Relay 3O energizes and closes its armature 31, thereby preparing a circuit for the stepping relay 50; at armature 32, the slow relay 30 connects ground to the release trunk conductor 6 and to a junction point between switching relay 10 and a contact of relay, and at armature 33, the slow relay 30 prepares the path for the vertical directive impulses for operating the motor magnet 60. hen the calling subscriber operates his calling device in accordance with a digit in'the desired partys num her, he interrupts the circuit of the line relay 20. This relay deenergizes a number of times corresponding to the dialled digit, and transmits, at each deenergization, a ground impuls to the motor magnet 60. The first impulse transmitted by the line relay may be traced from ground at armature 13 of the switching relay, armature 21 and its resting contact, upper windir ot the slow acting series rel-a" ll). armature 323 and its working contact, off normal springs 'iih vindin a' of the motor magnet 60 to battery. The rclt so relay does not return to normal during the rapid trinsn'iission of impulses due to its sluggish properties. The series relay which is also slow acting, onergizes upon the transmission of the first impulse and attracts arn'iature ll )2 paring a circuit for the stepping; relay 5t), and closes its armature substituting another path for the turthcr transmlsim of impulses, excluding otl' normal springs 70, which opened responsive to the first enerniaation ot the motor magnet (30 and con- .cquent rotation of the barrel member provided with h lie-ally arrangc'l teeth. Off normal sprii gs 72 close also upon the first step of the motor magnet. preparing a cirit the stepping relay 50. This circuit closed from ground armature ll worlrir gr contact. oii' normal springs 72. iinerrupter springs 61 operated by the r inagmet winding of the stepping relay to batter upon each d gizat-ion of magnet 60, l the circuit will not produce any changes ring the delivery of the vertical impulses to the motor magnet 60, ex-

- stepping clay. at its armature a holding circuit for its own iut du cept that the 51, prepares winding,

its will be remcanbcred the operation of the motor magnet is etlective to the barrel carrying helically arranged "eeth. Accordingly, the barrel rotates, and the shaittmoves vertically (l0\' .'11\ ard advancing the wipers to the desired row of contact The shaft. being plfiYltled vitl a projecting cam which advances vertically along the helically arranged teeth prevented from engaging" any of the pas inc; teeth due to the rapidly revel ii 1- barrel. Upon the termination of the directive impulses. however. the cam talies hold in the tooth directly below and the shaft thus positions the wipers opposite the desired level, and couples itself with the barrel member. A subsequent rotation of the barrel will therefore result in a rotation of the shaft and off the wipers.

This subsequent rotation is initiated automatically upon the termination of the vertical impulses and takes place as follows. The motor u'iae'net 6O deenereizes after the last directive impulse and closes its interrupter springs 61. The stepping relay 5O en rgizes now over a circuit including armature 4-1 and locks itselt in a circuit in eluding the interrupter springs 61 off nor mal springs 72 and its own armature 51 and its working contact to ground at armature 32. The stepping relay attracts armature 52. me iarin a circuit for the motor ma i D b net. which circuit is completed by the nornially closed contact operated by armature 41, upon the deenergization of the slow aeting series relay 4-0, which dcenerg'izcs shortly after the lastimpulse had been delivered the moto magnet. The motor magnet energizes over this circuit and rotates the l arrel by no step. The shaft, beingat this time firmly attached to the barrel, due to the projecting cam engaging: the helical tooth corresponding to the selected level will therefore ad ance the wipers into engagement with the first of bank conacts. Upon enn'jfizing. the motor magnet 60 opens its interrupter springs 61, thereby openine' the locking circuit oi the stepping relay 50. llelay dcnere'izes thereupon and opens at its ari'nature 52 the. circuit of motor magnet which deenergizes also, again closing its interrupter contact (31. The stepping relay 50 cannot energize over its original circuit due to armatures ll. and 51 beingopen. The further operation depends now whether the self ed trunk is busy or idle. It idle. the switching relay 10 operates immediately and switches the line conductors through to the nextswitch. For

the purpose of explanation, however. it shall be assumed that the trunk is busy.

Ground vill be encountered by test wiper 7G and stepping relay 50 energizes again over a circuit including arn'iaturc 12 and its resting contact armature 31 and its working contact, oil normal springs 72, intcrrupter springs (31 and winding of the stepping relay to battery. A short circuit is connected around the switching relay 10 at too same time, preventing it from energiz- 111g. This short Clf'llll includes ground atarmature 32, viuding of the switching relay 10. working contact and armature 31, rest ing contact and armature 12 to around encountered by the test wiper 76. Upon energizing, the stepping relay closes a locking circuit for its own winding. over its armature 51, and an 'ol'ierating' circuit for the motor magnet at its armature The wipers advance to the next set of bank contacts. These mutual operations between motor magnet 60 and the step iing relay 50 will be continued until an idle trunk is found.

Assuming this trunk to be the one shown in the drawing and designated 78, 79 and 80, there will be no ground encountered by test wiper 76. and the stepping relay 50 will not energize. The switching relay 10, however, being no longer short circuited. oper tes from ground armature 2', its wint off normal springs 72, interrupter springs 61, to battery over the winding of the stepping relay 50. The latter annot energize at this time. due to the high resistance of the switching relay.

too

Upon energizing, the switching relay 10 connects the trunk conductors through at its armatures 11 and 14, thereby deenergizing line relay 20; disconnects the test wiper '7 6 from the original circuit and connects it directly to the junction point of its own winding and the release trunk conductor 6, at its armature 12; and disconnects ground from the release circuit at its armature 18. The slow acting relay 3O deenergies and removes ground from the release trunk conductor 6 and from the switching relay 10 at its armature 32, and prepares the initiation of the release at its armature The seized switch, however, connected ground to the test conductor immediately upon being taken into use in a similar manner as the present switch by means ofa slow acting relay such as relay 30, and this ground is therefore propagated back over the test cond actor and test wiper 7 6 to the release trunk 6 leading to the preceding switch. The switching relay 10 remains in operated position throughout the duration of the call being connected to ground at therelease trunk and to battery in series with the stepping relay 50 over off normal springs 7 2 and interrupter contacts 61. The stepping relay does not operate in this circuitdue to the high resistance of the switching relay.

The calling subscriber operates his call ing device in accordance with the remaining digits in the desired partys number, setting the various selectors and finally the connector to establish connection with the wanted line terminals. No change occurs in the present switch during the operation of the subsequent apparatus or during the time the subscribers carry on a conversation.

The subscribers replace their receivers at the termination of the call. causing the removal of ground potential from the release trunk conductor and consequent release of the various switches. \Vhen the ground is removed from the release trunk, the switching relay 1O deenergizes, restoring its armatures to the positions shown in the drawing. The line relay 20 and the slow relay being deenergized at this time, a circuit will be closed for the operation of relay l0 from ground at armature 13, armature 21 and its resting contact, upper winding of relay 40, armature and its resting contact, off normal springs 71, and to battery over the lower winding of relay 40. Relay energizes and attracts its armaturedl, thereby completing a circuit for stepping relay 50, which circuit includes armature 41, off normal springs 72, interrupter contactsfi'l, and winding of relay to battery. Upon energizing, relay 50 completes a circuit for the motor magnet from ground at armature 32 and its resting contact, working contact and armature 52,

and motor magnet 60 to battery. The motor magnet operates and interrupts the circuit of relay 50 at its interrupter contact 61, whereupon relay 50 dcenergizes, interrupting the circuit of the motor magnet 60 at its armature 52. Accordingly, the motor magnet releases also, again closing the circuit of the stepping relay, and the stepping relay in turn, again closes the circuit of the motor magnet.

This mutual operation between the stepping relay and the motor magnet continues, and the motor magnet rotates the barrel again. A short survey of the circuit will reveal that the operations of the stepping relay and of the motor magnet depend upon the conditions of the off normal springs 71 and 72. As long as these contacts are closed, the operations are bound to continue, due to relay to being energized and maintaining ground connection at armature 41 for the operation of relay 50 which in turn depends on the closure of off normal springs 72. The motor magnet, in operating, rotates the barrel and the off normal springs will be oper-- ated and switched to normal as shown in the drawing, upon the barrel completing its circle of 360 degrees, preventing any further movement.

The shaft, carrying a cam at its upper end provided with a projection which, at the time engages one of the helically arranged teeth, participates in the rotation and advances the wipers over the remaining terminals in the level, however, without any eifect, due to the armature 31 being open at this time, i. e., the test wiper 76 is on an open circuit and cannot test any of the trunks. Recalling the mechanical operations occurring during the restoring rotary movement of the barrel, it will be remembered that the shaft is provided with a guide lever which proceeds towards a helical restoring runway. This guide lever strikes the runway shortly after the wipers have passed the last terminal set in a level and lifts the shaft and with it the projection of the shaft cam out of engagement with the helical tooth on the revolving barrel. The latter continues to rotate and the shaft rests with the guide lever engaging the helical upwards sloping runway. Upon the barrel taking its last step, it operates the off-normal contacts as described, preventing any further rotation, and moves a restoring lever momentarily, which releases a special arm. The latter rotates ,under the force of a spiral spring, catches the guide lever of the shaft and moves it upwards into its normal position, along the in cline of, the helical runway. At the end of the restoring movement of the shaft, the shaft guide lever and the special restoring arm engage their respective stops, while the projection of the shaft camis again posiill) till

tioned upon the barrel in front of the first helical tooth. The switch now normal and miiy be used for a subsequent call.

Although I have illustrated and described a particular switch embodying the principles of my invention, it is to be understood that I do not dish to limit myself to such use. The principles involved ob iously lend themsclv to wide application in a variety o without departure from the spirit of field 0t my invention.

l'v ha I laim as my mvent'on is:

J 1. an automatic switchin mechanism havin a vertically and radially movable shaft provi ed with wipers, terminals ar anned m horizontal rows a ccssi is to said wipers, an elcctromac net having; only one pawl operated thereby. means including said electromag net and pawl for moving said wipers veri ally to select a certain desired ro v, and tor the). moving! said vipers radially to sei rminals within said row, said moving said 3. An automatic remotely controlled switching: mechanism having shalt provided with vipers, terminals accessible to said wipers, means including an electromagnct tor mov. said shait lust lngitudinally and then a: lly to establish a tempo 2 ry connection between said wipers and certain of said terminals, said means also operative for then moving said wipers back into normal position. said wipers describing cgrees, whenever used for L. An

ection.

swi tchinc' a circle 0: d i

establishing a con automatic mechai contri'illed a shalt provided tern 'nals accessible to i l u in an electromagtor L "dinal directively controlled 1110-.O11'1G11t of said shaft executed by force of gravity, said means also operative tor automatically effecting a radial movement of id shaft to position said vipers upon certain terminals, and again operative tor moving said wipers in the same radial and opposite longitudinal direction into its normal position.

5. An automatic remotely switching mechanism having a shaft.- provided vith wipers, terminals accessible to said wipers, means including a electromag- I Sn controlled remotely controlled switching; mechanism having a shaft provided with wipers, terminals acccssible to said wipers. means including: an ccctromagnet tor ettectin a ton udinal directively controlled moven ent 0. said shr' t executed by force of gravity, l.--:o opentive for auton l a radial movement of said shaft wipers upon certai termin:

tion said cal 1n *ans released by said cl yoniagnct lor moving said wipers in the me radial. direction into normal position.

'7. In automatic remotey controlled switching mechanism having, a shaft prr :-d with wipers, terminals accessible to said wipers, means iiiciudingg an electromagnct for eiicctiug a longitudinal dircctivelv controlled movementof said .iliait executed by force oi 'ravitv. said means also operative t'or autoimitically cilcctine a radial movnnent oi said shaft to position said wipers upon certain terminals, and mechanical means operating independently of said CL'i'l')ll1tl; Il1Q for moving said wipers in the same adn l direction into normal position.

8. In automatic remotely controlled switching mechanisn'i having a shaft provided with wipers, terminals accessible to said wipers, means includinp' an electromagnet for e'li'ecting a lonsritudina dircctively controlled movement of said sha it executed by force of vity, said means also operative for auton'iaticalzy ell'ectingr a radial movement of said shat't to position said wii lers upon certain terminals, and mechanical means perahle independently of but com trolled by paid elcctron'i snot tor noviufl' said wipers in the radial direct ion into normal position.

9. In automatic remotely controlled switching mechanism having a shat't provided with wipers. terminals Zlh'L'L sible to said wipers. means including an e ectromagnet for effecting alone'itudinal dircctively controlled movement of said shaft executed by force of gravity, said means also opera tive for automatically eliectin a' a radial movement of said shaft to position said wipers upon certain terminals. and mechanical means operable indi-ipendenlly of and after said electromagnet has ceased to operate for moving said wipers in the same radial direction into normal position.

10. In automatic remotely controlled )Ilii lit) ' of 360 degrees switching mechanism having a shaft. provided with wipers, terminals accessible to said wipers, means including an electromagnet for ell'ecting a longitudinal directively" mechanical means for restoring said wipers to normal position.

11. In an automatic remotely controlled switching mechanism. terminals arranged in groups in horizontal rows, a shaft provided with wipers longitudinally movable by gravitational force to select a certain row and axially mo *able to select terminals within said row, and a single electromagnetic means for controlling and executing the movements of said shaft, including its restoring movements.

12. In an automatic remotely controlled switching mechanism, a plurality of terminals, wipers movable in two dimensions provided for establishing connection with said terminals, said wipers being locked in a normal. position while not in use. and a single electromagnetic means operative for executing the movements of said wipers in estab lishing connection with certain of said terminals and again operative for restoring said wipers to normal position.

13. In an automatic remotely controlled switching mechanism, a set of terminals, wipers resting in a normal position out of engagement with said terminals, and a single electromagnetic means operative formiccessively moving said wipers in two directions to engage said terminals and again operative for restoring said. wipers to normal position by moving them in like and opposite directions.

14. In an automatic remotely controlled switching mechanism, a setof terminals, wipers resting in a normal position out of engagement. with said terminals, 211K. a single electromagnetic means operative for successively moving said wipers in two dimensions to engage said. terminals and again operative for restoring said wipers to normal position, said restoring movement involving different paths than the setting movement.

15, In an automatic remotely controlled switching mechanism, a set of terminals, wipers resting in a normal position out of engagement with. said terminals, and a single electromagnetic means operative for successively moving said wipers in two dimensions to engage said tern'iinals andagain perative for restoring said wipers to normal position, said wipers describing a circle for every connection.

16. In a switching mechanism, terminals, wipers resting in a normal position out of engagement with said terminals, a single electroinagnetie means operative for successively moving said wipers in two dimensions to engage certain of said terminals, the movement of the tirst dimension being executed by force of gravity but under control of said electromagnetic means, said electromagnetic nleansbeing again operative for restoring the wipers to normal position over ditlerent paths than those employed in the setting movements.

17. In a switching mechanism, a shaft provided with wipers, terminals of trunk lines arranged in groups in horizontal rows accessible to said wipers, a member provided with a. row of helically arranged notches, directively controlled means for moving said member radially to advance said shaft longitudinally by force of gravity to position said wipers opposite a certain row, said shaft being out of engagement with said member during said movement, means on said shaft for engaging said member at the end of said directively controlled movement, means for then operating said member to continue its radial movement to advance said wipers horizontally to select an idle trunk, and mechanical means for restoring said shaft to normal position.

18. In a switching mechanism, a shaft provided with wipers, terminals arranged in groups in horizontal rows accessible to said wipers, a radially movable member provided with a circular row of teeth, said member being operable under directive control for effecting a longitudinal movement of said shaft executed byforce of gravity to position said wipers opposite a certain row and also operable automatically for effecting an axial movement of said shaft to position said wipers upon certain terminals within said row, and again operative for restoring said shaft to normal position.

I 19. In a switching mechanism, a shaft provided with wipers, terminals arranged in groups in horizontal rows accessible to said wipers, a radially movable member provided with a circular row of teeth, said. member being operable under directive control for effecting a. longitudinal movement of said shaft executed by force of gravity to position said wipers opposite a certain row, and also operable automatically for effecting an axial movement of said shaft to position said wipers upon certain terminals within said row, and again operative for restoring said shaft to normal position, said wipers describing a circle of 360 degrees.

20. In a switching mechanism, a shaft provided with wipers, terminals arranged in groups in horizontal rows accessible to said wipers, a radially movable member provided with a circular row of teeth, said member being operable under directive control for ellecting a longitudinal movement of said shaft executed by force of gravity to position said wipers opposite a certain row, and also operable autoimitically for effecting an axial movement of said shaft to position said wipers upon certain terminals within said row, and again operative for initiating the restoring movement of said wipers to normal position, said restoring movement taking place over different paths than the setting movement and involving n'icchanical means operative independently of and after said member provided with circular teeth has restored to normal.

21. In a switching mechanism, terminals, wipers movable in two dimensions and nor mally resting out or engagement with said terminals, a single motion operating member, a device for storing up mechanical ten sion, means for operating said member to store up energy in said device and to move said wipers into temporary engagement with terminals. and means controlled by said member For releasing said energy to effectthe restoring movement of said wipers.

22. In a switching 1110(l1i11'1l51'11, terminals, wipers movable in two dimensions and non mally resting out of engagement with said terminals, a single motion operating member, a device for storing up mechanical ten sion, means for operating said member to store'up energy in said device and to move said wipers into temporary engagement with terminals. and means controlled by said member for releasing said energy to effect the restoring movement of said wipers, said wipers describing a circle of 360 degrees whenever used tor establishing a connection.

23. In a switching mechanism, terminals. wipers movable in two dimensions and normally resting out of engagement with said teri'ninals, a single motion operating memher, a device for storing up mechanical tension. means for operating said member to store up energy in said device and to move said wipers into temporary engagement with terminals, and. means controlled. by said member for releasing said energy to ciect the restoring movement of said wipers. said restoring movement taking place in a direction continuous to the setting movement of said wipers.

24s In a switching mechanism, terminals arranged in groups in horizontal rows. a shaft provided with wipers longitudinally movable to select a certain row and axially movable to select terminals within said row, a radial y movable member for controlling the movements of said shait including the. restoring movement, a lever arm. a spiral. spring associated with said member and said lever arm. means for operating said member to effect the setting operation of said shaft and for storing up energy in said spiral spring, and means for releasing said energy stored up by said spiral spring to ctl'ectthe restoring movement of l wipers, said restoring movement tailing place in the same direction as the rotary setting movement.

25. In a switching mechanism. terminals, vertically and horizontally movable switching members tor cstabli ling temporary connections with said teiziiinals. said members resting in a normal position out of engagement with said terminals-2. a member provided with a circular row of teeth movable only radially in one direction for controlling the mov nents o'l said. wiper: a lever arm, a spiral spring attached to said member and said lever arm. means lor operating said member to ell ect the vertical and horizontal setting movements of said wipers and for storing up tnergy in said spiral spring, and means controlled by said member for releasing said energy to ell'ecl' the restoring movements of said wipers, said wipers descril'ng a circle ot' ltlll degrees.

:26. In a switching met-bani m. terminals, 'ipcrs movable in two dimensions and non mally re ing out of engagement with said terminals, an operating device, means for actuating said device to move said wipers into temporary engagement with terminals, an obliquely ascend traclz,

ling semi-circuhir and means controlled by said operating device for restoring said wipers to normal along said track.

27. In a switching mechani m. terminals, wipers movable in two dimensions and nor mally resting out of cngzjagemcnt with said terminals, an operating device. means for actuating said device to move sa d wipers into temporary engagementwith terminals. a helically ascend ng runway. and means released by, but operating independent y o'l said operating device for restoring said wipers to normal along said runway.

28. In a switching inechanisn'i. terminals, wipers movable in two dimcn.- ion.- and normally resting out of cneagenwnt with said terminals, an operating device, mea as for actuating said device to move said wipers into temporary engagement with termina s. a helical incline, and operations initiated by said operating device for e'tl'e ting the re toration of said wipers to normal along said incline, said restoring morement being continuous to said setting movement.

29. In a. switching mechanism, rminals, wipers movable in two dimensions and nor-- mally resting out of engagement wi h aid terminals, an operating device. means For actuating said device to move said wipers into temporary engagement with terminals, a helical continuous incline, and means controlled by a step-by-step movement of said operating device for effecting the restoration of said wipers to normal along said ion ill]

lio

continuous incline, said wipers describing a circle of 360 degrees.

30. In a switching mechanism, tern'iinals, wipers movable in two dimensions and normally resting out of engagement with said terminals, an operating device, means for actuating said device tomove said wipers into temporary engagen'ient with terminals, a helically ascending guide track, and mechanical means operatively effective to the exclusion of said operating device for restorii'ig saidhvipers to normal position along said guide track, said restoring movement involving different paths than the setting movement. I

31. In a switching mechanism, terminals, wipers resting in anormal position out of engagement with said tGIIIilDELlS, and means operative for moving said wipers successively in two dimensions to temporarily engage terminals and again operative to restore said wipers to normal position in a continuous helical motion.

32. In a switching mechanism, terminals, wipers resting in a normal position but out of engagement with said terminals, and means operative for moving said wipers successively in two dimensions to temporarily engage terminals and again operative to restore said wipers to normal position in a continuous helical motion, said wipers describing a circle of 360 degrees.

33. In a switching mechanism, terminals, wipers resting in a normal position but out of engagement with said terminals, and means operative for moving said wipers successively in two dimensions to temporarily engage terminals and again operative to re store said wipers to normal position in a continuous helical motion, said restoring movement being in a direction continuous to the setting movement.

34. In a switching mechanism, terminals arranged in groups in horizontal rows, a plurality of movable stops, a shaft provided with wipers and resting in a normal position suspended on one of said stops, means for successively moving said stops with relation to said shaft, said shaft moving vertically by force of gravity in accordance with the movement of said stops and engaging at the termination of said movement the stop corresponding to the number of steps taken, positioning said wipers opposite a desired row, said means again operative for moving the stop engaged tosaid shaft to advance said wipers horizontally within said row to select terminals.

35. In a switching mechanism terminals arranged in groups in horizontal rows, a plurality of helically arranged stops, each corresponding to a certain row, provided on a circular radially movable member, a. shaft carrying wipers and resting suspended upon said member in a normal position preceding said stops, means for moving said member to displace said stops relative to said shaft for advancing said shaft vertically by force of gravity, said shaft engaging at the termination of said movement the stop corresponding to a certain row, positioning said wipers opposite thereto, said means again operative for moving said member to operate said shaft radially to advance said wipers to engage certain terminals within said row.

36. In a switching mechanism, terminals arranged in groups in horizontal rows, a radially movable member provided with helically arranged stops one for each row, a shaft carrying wipers and resting suspended upon said member in a normal position preceding said stops, ineans for moving said member under directive control to successively advance said stops with relation to said shaft for moving said shaft vertically by force of gravity, said shaft at the termination of said directive movement engaging the stop corresponding to a certain row posi tioning said wipers opposite thereto, said means then operative for moving said meniber automatically to successively advance the stop engaging said shaft to move said wipers into engagement with certain terminals within said row.

87. In a switching mechanism, av wiper set having a plurality of wipers rotatable through arcs of 360 degrees in each of a plurality of planes, and means for maintaining a continuous electrical connection to said wipers.

38. In a switching mechanism, a wiper set rotatable in a continuous direction in each of a plurality of planes, and means for maintaining a continuous electrical connection to said wiper set.

39. In a switching mechanism, a shaft carrying wipers, means for moving said shaft longitudinally and for rotating it through an arc of 360 degrees, and means for maintaining a continuous electrical connection to said wipers.

40. In a switching mechanism, a shaft carrying wipers, means for moving said shaft longitudinally and for rotating it through an arc of 360 degrees, a second shaft parallel to the first and movable longitudinally with it, and means on said second shaft for maintaining a continuous electrical connec tion to said wipers.

In witness whereof. I hereunto subscribe my name this 25th day of August, A. D.,

HANS SENGEBUSCH. 

